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Sept. 16, 2011 -- Ever wonder why some people immediately see the bright side of just about any situation and seem to make friends wherever they go?

Turns out, it may be in their genes. The findings appear online in the Proceedings of the National Academy of Sciences.

Researchers have zeroed in on a possible genetic basis for optimism, self-esteem, and mastery (the belief that you have control over your own life and destiny). It’s rooted in the hormone oxytocin, also known as the love or cuddle hormone. Oxytocin is known to be plentiful in breastfeeding women and is released by men and women during orgasm.

A little chunk of genetic material on the oxytocin receptor gene may influence these personality traits. Exactly how the gene affects the release of oxytocin is not fully understood. A combination of two variants -- an “A” and “G” -- are located in this small area.

In the study, 326 study participants answered questions about their optimism, self-esteem, and mastery. Researchers analyzed genetic material in their saliva to see how the variants of the gene correlated with the self-assessments. Participants also completed a standardized tool that measures depression.

A Look at the Gene

The gene can backfire on you too.

People with a gene variation including one or two A’s were found to have less optimism, mastery, and self-esteem, and more symptoms of depression than people with a variation including two G's.

If you have two G’s however, you are more likely to see the world -- and your role in it -- in a positive light.

“If you have an A, the deck is stacked against you somewhat,” says Shelley E Taylor, PhD. She is a distinguished professor of psychology at the University of California at Los Angeles. Taylor credits her graduate student Shimon Saphire-Bernstein with pinpointing the region on the gene that hosts these traits.

The combination affects how you see the world and your role in it. But you are not destined to be happy or sad based on your genetic make-up. Not at all, she says.

Genes predict behavior, but they are not the be-all, end-all. “There is a lot of room for environmental variations, like how you were raised and the life experiences that you have had,” she says.

It’s complicated, says Philip D. Harvey, PhD, a professor of psychiatry and behavioral sciences at the University of Miami Miller School of Medicine.

Rarely does one gene influence any one personality trait, he says. “My guess is that there are multiple gene interactions involved."

“There are genes that influence the way you process emotional information, and this gene affects the way you see the world. But that doesn’t mean you can't change the way you look at the world,” he says.

Reach Out and Connect

When Paul J. Zak, PhD, founding director of the Center for Neuroeconomics Studies at Claremont Graduate University, Calif., first started to read the study, he was skeptical.

But it is “pretty convincing,” he says.

Still, genes aren’t destiny, Zak says. “Some people may have a genetic leg up, and if your parents treat you well and you don’t experience any childhood trauma, you may develop richer social networks."

“We may not all have the genetic predisposition for happiness and we may not release enough oxytocin. But there are things that we can engage in -- from social media to dancing,” Zak tells WebMD.

“Whatever helps you connect with others will help you improve your life,” he says. “Jump on the social connection bandwagon now.”

Alan Manevitz, MD, a psychiatrist at New York City's Lenox Hill Hospital, agrees. “Just because you have a gene doesn’t mean you are fated to be happy or sad, it means you are more vulnerable to these traits."

“This speaks to the idea of developing coping mechanisms early,” he says.